Firewall

Firewall

— a specialized type of router, the main feature of which is advanced filtering and traffic processing capabilities, as well as additional security features. The official name of such devices is “firewalls”, which quite accurately describes the main way they are used: filtering traffic between the serviced network and the rest of the environment (both neighboring “LANs” and the Internet). All firewalls must have protection against DoS attacks and content filtering (see "Security"); most often, other security features are provided, but their set should be clarified

Note that a firewall can also be created purely by software — for example, on one of the computers on the local network, which plays the role of an intermediate node. However, it is easier and more reliable to use specialized equipment for this: separately made firewalls are easier to configure, and their hardware is initially optimized for the corresponding tasks.